ATHENS/WASHINGTON, July 10 (Reuters) - A window pulled a passenger out after it detached from its hinges during a Ryanair flight shortly after takeoff from the Greek city of Thessaloniki on Friday, forcing the plane to make an emergency landing, two airport sources said.

The plane was scheduled to fly from Thessaloniki to Memmingen Airport in Germany, but Ryanair said in a statement that the aircraft returned to Thessaloniki "when a window broke off (next to) a passenger during the flight." The cause of the window break is not yet clear.

The airline explained that one person received medical attention, but did not provide details about the reason.

The US Federal Aviation Administration confirmed that the aircraft was a Boeing 737 NG. Boeing has not yet commented.

A similar incident was recorded in 2018 on board a Boeing 737 NG aircraft, raising questions about a possible link between the two incidents.

Local media in Greece reported that a piece of the engine broke off and smashed the window early in the flight on Friday.

This caused a drop in cabin pressure and partially pulled a passenger out of the window. Two airport sources familiar with the incident confirmed these details to Reuters.

The airline has not yet responded to an emailed request for comment on the details of the incident, as well as for confirmation of the aircraft model and engine.